Hypodermic syringe plunger retarding means



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L. EISELIE HYPODERMIC SYRINGE PLUNGER RETARDING MEANS Filed Dec. 15, 1931 3 Sheets-Sheet 1 IN VEN TOR. I e/uv Z'IJELE A TTORNEYS.

I N V EN TOR.

A TTORNEY Filed Dec. 15, 1931 3 Sheets-Sheet 2 L EISELE HYPODERMIC SYRINGE PLUNGER RETARDING MEANS W, ms L. EISELE w fi HYPODERMIC SYRINGE PLUNGER RETARDING MEANS Filed Dec. 15, 1931" asheets-sheet a IN VEN TOR.

I A 4A/ f/JELE BY 4 ATTORNEY v Patented Sept. 17, 1935 [TED STATS su tes OFFIQ HYPODERWIHC SYRINGE PLUNGER RETARDING MEANS 11 Claims.

My invention relates to hypodermic syringes and particularly to improvements in means for restraining the movement of the plunger.

Syringes used by doctors and dentists in making hypodermic injections have been provided with devices to frictionally engage a surface of the plunger to prevent the plunger from accidentally dropping out of the barrel and to restrain movement of the plunger when operating the syringe. However, such devices cause wear and/or scratches on the surface of the plunger Where the frictional engagement occurs and shortens the life of the syringe, due to the fact that the worn places and scratches cause leakage.

The primary object of my invention is to provide a device which can be readily fitted on existing types of hypodermic syringes, or supplied already fitted thereon, and carrying elements to contact the plunger as it is moved inwardly or outwardly relative to the barrel but without frictionally engaging the plunger so that the wear and scratches above mentioned will be obviated while the operation of the syringe will be improved and the life and utility of the syringe will be increased.

The specific objects of the invention include the provision of simple but eifective devices for the accomplishment of the foregoing object Which can be readily applied to the syringes in a manner and position which do not interfere with the operation of the plunger, and which are not disturbed or afiected by handling and operation of the syringe.

The invention is applicable to hypodermic syringes regardless of the nature or composition of the material of which the syringe and plunger are made, and the accompanying drawings are merely illustrative of a known type of syringe and do not limit the invention to use with any particular type of syringe.

In the drawings, Fig. 1 is a vertical central sectional View through a hypodermic syringe with the plunger and one type of restraining device embodying the invention shown in elevation;

Fig. 2 is a sectional view on the line 22 of Fig. 1;

Fig. 3 is a perspective View of the restraining device shown in Fig. 1;

Fig. 4 is a View in elevation of a hypodermic syringe with another type of restraining device embodying the invention applied thereto;

Fig. 5 is a view taken on the line 55 of Fig. 4;

Fig. 6 is a view similar to Fig. 4 showing another type of restraining device embodying the invention;

Fig. 7 is a view on the line l'l of Fig. 6;

Fig. 8 is a plan view of the blank from which the device shown in Fig. 6 is constructed;

Fig. 9 is a side elevation of another modifica- 5 tion of the invention;

Fig. 10 is a view on the line iiiof Fi 9;

Fig. 11 is a View on the line H-H of Fig. 12;

Fig. 12 is a front elevation of another modification of the invention; 10

Fig. 13 is a perspective View of still another modification of the invention;

Figs. l4, l6, and 18 are side elevations of different modifications of the invention; and

Figs. 15, 17, and 19 are top plan views of the 5 modifications shown in Figs. 14, 16 and 18, respectively.

Referring to the drawings, the numeral Ill designates the barrel of a hypodermic syringe, having a tip H to receive the usual needle, not 20 shown, and at its upper end having the lateral flange 52, which has parallel opposite straight faces 13, and opposite curved faces M. The plunger is indicated at l5. The numerals id-itl inclusive are used throughout the drawings to 25 designate the same parts in all figures where the syringe is illustrated.

Although the plunger is indicated as having a roughened outer surface which contacts the smooth inner surface of the barrel Hi, there would 30 be considerable free movement of the plunger within the barrel, sufficient in many cases to permit of the plunger dropping out of the barrel ii the syringe were inverted or nearly inverted. When the plunger is pulled upwardly liquid is 35 drawn through the needle and tip it into the barrel and when sufiicient liquid has been drawn into the barrel the plunger may leave the surface of the liquid. To prevent this and to facilitate manipulation of the plunger with a steady 40 and even movement, I provide the frame it, Figs. F3, which may he formed of a piece of Wire of resilient character bent as shown in Fig. 3, to provide a central curved arm 11 to abut the outer surface of the barrel l8 beneath the flange i2, and oppositely disposed U-shaped portions 18 to engage around the flange l2, and inwardly therefrom the U-shaped portions it? at opposite sides of the plunger. When the frame It is on the syringe barrel, the U-shaped portions l8 are disposed in a horizontal plane, and the U-shaped portions iii are inverted in a substantially vertical plane.

It will be noted that the frame is open at the side opposite to the curved arm ll so that, as Shown in Fig. 2, the device may be applied. to

the syringe barrel by simply slipping one of the curved faces 14 of the flange l2 into the members l8 on the open side of the frame and then pushing against the arm I! until both pairs of loops I8 slide on to the straight faces 13 of the flange l2 and the arm I! is disposed under one of the curved faces M of the flange or against the barrel.

If the portions I?! were bent inward toward each other sufficiently to contact the surface of the plunger there would obviously be a frictional contact which would cause scratching or wear on the surface of the plunger and destroy the carefully prepared contour and finish of the plunger which is designed for nice engagement in the barrel I 0. To overcome this, I provide rollers on the upper arms 2! of the U-shaped portions l9, and these rollers may be conveniently secured to the arms 2! by partly splitting the rollers as at 22 to their center opening 23, so that they may be opened and positioned on the arms 2|, by passing the arms through the split 22, until they are received in the openings 23, after which the rollers are clamped together to close the split sufiiciently to prevent accidental displacement of the rollers.

It should be apparent that the relative distance between the respective arms 2| may be varied by bending the members [9 toward or away from each other so that the rollers 23 may be adjusted for proper contact with the surface of the plunger I5, and as the wire is resilient the rollers will bear against and be biased toward the plunger so that the plunger can be moved up and down in the barrel under restrain and yet without any scratching or wear being imparted thereto by the restraining device.

I wish it to be understood that one of the rollers may be omitted under the structure shown in Figs. 1-3, and in Figs. 4 and 5, I have shown a modification wherein a single elongated relatively thin roller 25 is carried on a frame 26. The frame comprises a curved portion 2'! which fits beneath the flange of the barrel and partially embraces the barrel and at one side of the barrel the arms 28 embrace the flange and above the flange the arms are offset from the top of the flange and bent inwardly toward each other to provide arms 29 on which the roller 25 is carried.

The construction and arrangement shown in Figs. 4 and 5 provides a very simple structure and the parts can be readily assembled by bending one of the arms 29 out of alinement with the other or pulling the arms apart so that their ends can be engaged in the opening of the roller, whereby the roller will be rotatably carried by said arms and disposed against the surface of the plunger. The device shown in Figs. 4 and 5 is applied to the syringe by removing the plunger and then sliding the frame over the flange with the roller and arms 28 moving across the flange until the roller has substantially crossed the opening in the barrel, after which the plunger is inserted for engagement with the roller, and as is obvious, maintains the frame against displacement from the syringe while the resilience of the material of which the frame 26 is formed biases the roller toward the plunger with sufficient force to prevent the plunger dropping accidentally from the barrel and to facilitate even operating movements of the plunger.

In Figs. 6-8 I have shown another form of device embodying the invention generally similar to the idea embodied in the device shown in Figs. 1-3 but wherein the device is constructed of flat sheet metal from which the blank, shown in Fig. 8, is stamped and then bent to the form shown in Figs. 67. The blank comprises a central substantially c-shaped body 30 having at its top and bottom relatively thick portions 3| connected by a curved intermediate portion 32. Extending from the end of each of the portions 3%, is an arm 33 carrying at its outer end a relatively narrow elongated cross head 34 which terminates at both ends in a reduced tip 35.

The blank shown in Fig. 8 is fashioned to provide the frame shown in Figs. 6-8 by bending the portions 3| until their curvature is approximately that of the flange or suflicient to maintain the frame on the syringe in the position shown in Fig. 6, where the intermediate portion 32 is disposed against the top of the flange and the portions 3| embrace the opposite sides of The arms 33 are bent back upon the the flange. portions 3| along the line where the arms meet the ends of said portions until the arms are substantially perpendicular to the plane of portion 32, and then the ends of the heads 34 beyondthe sides of the arms 33 are bent inwardly toward each other at substantially right angles to the arms 33, and the tips 35 are bent inwardly to ward each other and at substantially right angles to the portions 36 of the head 34. A roller 31 is rotatably mounted'on the respective tips. I

Referring to Figs. 67, the device is applied to the syringe by sliding the portions 3| on to the opposite sides of the flange until the portion 32 is disposed on the flange and the rollers are substantially centered with respect to the plunger for contact therewith. The arms can be bent toward or away from each other until proper contact is had between the rollers and the plunger, and as will be apparent, as the plunger is moved inwardly and outwardly the rollers will revolve on the tips 35, and due to the resilience of the material of which the device is formed, will restrain the movement of the plunger 'toprevent it from accidentally dropping out of the barrel if the syringe is inverted, and will afford an even movement of the plunger during operation thereof.

Referring to Figs. 9-10,'it will be noted that the restraining device may also be made with the roller carrying parts struck up from or mounted at the inner portion of a substantially U-shaped plate having a portion 33 corresponding to the approximate size and configuration of one end of the flange l2, and having channels 39 at opposite sides to embrace the edges of the flange to hold the device in position. A portion or strip ti) is bent up at the inner edge of the portion 33 and has lateral wings ll turned in and provided with openings to receive a pin 42 on which the roller '43 is rotatably mounted. Referring to Fig. 9, it will be noted that the strip is bent upwardly and slightly backwardly so that under the natural resiliency of the material the strip will tend to move inwardly, whereby it will urge the roller 43 against the surface of the plunger iii. The device shown in Figs. 9-10 can be readily applied simply by sliding the channels '39 on the flange l2 until the roller 53 contacts with the plunger. The device can thus be applied to the syringe with the plunger in the barrel.

In Figs. 11-12, I have shown a construction similar to that shown in Figs. 9-10 except that the plate 38 is formed to the approximate size and shape of the top of the flange I2 and will cover the entire top surface of the flange when the device is positioned thereon with the channels 39 embracing the sides of the flange. Under this construction I can provide. two strips it carrying the rollers d3 at opposite sides of the plunger, the strips being bent up from the inner edge of the plate 38 adjacent the plunger. Under the construction shown in Figs. 11-12, it would be necessary to remove the plunger from the barrel in order to slide the plate 33' on to the flange with the channels 39 embracing the sides of the flange if the strips dd are located on the plate in position to hold the rollers at right angles to the channels 39. However, it is obviously possible to position the strips id parallel to the channels 3%! so that as the plate moves on to the flange, the rollers will engage opposite sides of the plunger.

In Fig. 13, I have disclosed another modification of the invention similar to that shown in Figs. 9-12 except that the plate 38", having the side channels 38" to embrace the sides of the flange l2, has struck up therefrom at opposite sides of the plunger and out of alinement with the center of the plunger spaced pairs of arms M, the upper ends of which are looped or bent to provide bearings id for the pins carrying the rollers i'i. Devices embodying this form of the invention may be applied to the syringe in the same manner described in connection with Figs. 9-12.

In 14-19, I have shown several modifications of the invention, wherein the rollers are supported on a frame constructed of wire as in Figs. 1-5 instead of from a flat metallic form as in Figs. 6-13. Referring to Figs. 14-15 a strip of wire is bent at its middle to form an abutment 8 to engage the barrel it under the flange l2 and at opposite sides of the abutment til the wire is bent upwardly and inwardly to form the U-shaped arm 49 to engage the edge of the flange l2, and is then bent from the upper end of the arm 49 at substantially right angles to the plane of said arm to form a support 58 for the roller 5!, and then is bent outwardly and downwardly to form another U-shaped arm 52 in alinement with the arm 35. The free end of the wire 53 may be bent parallel with the support 50 to be disposed under the flange 12. Under this construction the rollers would be applied on the portions 5d before the wire is bent outwardly and downwardly to form the arms 52 so that the rollers would be positively retained on the frame. As is obvious from Fig. 15 this form of restraining device is applied to the syringe by sliding the opposite pairs of arms 5952 on to the flange l2 until the rollers 50 engage the plunger or until the abutment d3 meets the barrel it. It should be obvious that the rollers can be adjusted with respect to each other and with respect to the' plunger by bending the wire so as to bring the portions 56 closer together or position them further apart as desired. I

The device shown in Figs. 16-17 is substantially identical with that shown in Figs. 14-15 except that the abutment d8 of Figs. 14 and 15 is dispensed with and the U-shaped arms lil at opposite sides of the flange i2 are connected by a middle portion 54 of the wire which is disposed on top of the flange, the arms 49 being formed by bending the wire downwardly and inwardly instead of upwardly and inwardly and then bending the wire to form a connecting portion 55 to be disposed beneath the flange, and then bending the wire upwardly and inwardly to form the arms 59 and then bending the wire back toward the portion 55 to form a support 56 for the roller 51, the end of the wire 53 being bent slightly to retain the roller on the portion 55. Under this arrangement, the device may be made substantially complete with the exception of the roller and the roller may be applied at any time to the portion bit, after which the end 58 is bent to; retain the roller.

The device shown in Figs. 18-19 is the same as that described in connection with Figs. 16-17 except that the portion connecting the opposite spaced arms 59' is bent upon itself to form a lip or hook 59 to engage one end of the flange it? so that as the device is applied to the syringe by sliding the same on to the flange, with the arms 49, 5D embracing the straight edge of the flange, the movement is stopped when the lip or hook 59 abuts the curved edge of the flange H2, at which time, according to the predetermined dimensions of the respective parts, the rollers 51 will be in engagem nt with the plunger.

Wherever the terms roller or rollers are used in the foregoing description and in the claims, such terms are used to designate any rotatable elements mounted for engagement with the plunger whether such elements be spherical, cylindrical, or oval shaped, and although I have described the rollers in connection with Figs. 10-13 as being tubular cylindrical rollers mounted on pins, it should be perfectly obvious that the rollers may be formed in one piece as by having the part ii, in Fig. 13 for instance, a solid cylindrical body with projecting reduced ends corresponding to the pins 66. By making the rollers in one piece with the reduced ends to be received in the bearings on the frame, the cost of manufacturing and labor in assembly can be further reduced.

I claim:

1. A restraining or controlling device for the plunger of a hypodermic syringe of the type having a lateral flange at the top of the barrel comprising, a frame slidably mountable on said flange independently of the barrel, said frame having a substantially straight yieldable bearing part to extend across the top of the barrel of the syringe and in spaced relation thereto, a roller resiliently and rotatably supported on said frame above said flange for engagement with the side of the plunger of the syringe to non-frictionally restrain movement of the plunger.

2. A restraining or controlling device for the plunger of a hypodermic syringe of the type having a lateral flange at the top of the barrel comprising a frame mountable on said flange independently of the barrel by sliding movement across said flange, at least one substantially straight bearing part resiliently supported by the frame and extending above said flange in spaced relation thereto, and a roller rotatably mounted on said bearing part for engagement with the plunger of the syringe to non-frictionally restrain movement of the plunger.

3. A restraining or controlling device for the plunger of a hypodermic syringe of the type h ing a lateral flange at the top of the barrel comprising a frame, U-shaped arms on said frame to embrace opposite edges of the flange whereby said frame is slidably mountable on said flange independently of the barrel of the syringe, diametrically oppositely disposed upstanding straight bearing portions on said frame above the flange,

and a roller rotatably and yieldably carried on each of said portions for engagement with opposite sides of the plunger to non-frictionally restrain movement of the plunger.

4. The structure of claim 3 wherein the plunger serves to retain the device against displacement by sliding movement from the flange so long as it is associated with the barrel.

5. A restraining or controlling device for the plunger of a hypodermic syringe of the type hav-g ing a lateral flange at the top of the barrel comprising a plate having channels at opposite sides to embrace opposite edges of the flange to hold the plate on said flange, said plate being slidably held on said flange by said engagement between said channels and edges, at least one upstanding resilient support on said plate, and a roller rotatably mounted on said support for non-frictional engagement with the plunger of the syringe.

6. The structure of claim 5 wherein the channel members cover substantially the entire surface of the edges of the flange which they engage and the plate is disposed on top of said flange.

7. A device of the character described comprising a frame of resilient material having U- shaped members at opposite sides of the frame, at least one inverted U-shaped member above said first members and extending thereabove, and a roller mounted on said inverted U-shaped memher.

8. A restraining or controlling device for the plunger of a hypodermic syringe comprising a sheet of resilient material having opposite sides bent to channel formation, portions of said sheet being bent upwardly and provided With bearings,

a pin mounted through said bearings, and a roller mounted on said pin.

9. A restraining or controlling device for the plunger of a hypodermic syringe of the type having a lateral flange at the top of the barrel comprising a frame having confronting spaced side portions of channel formation to engage around and slide along opposite edges of the flange, means on said frame for engaging the plunger to restrain movement thereof, and a depending portion on said frame for engagement with one end of the flange intermediate said edges to limit movement of the frame in one direction relative to the plunger and locates said means in proper relation to the plunger.

10. A device of the character described comprising a frame of resilient material having U- shaped members at opposite sides of the frame to engage opposite sides of the flange of a syringe barrel, at least one U-shaped member on said frame above said first members, and a roller mounted on said second U-shaped member.

11. A restraining or controlling device for the plunger of a hypodermic syringe comprising a frame detachably mounted on the syringe, said frame having upstanding spaced members alined in pairs at opposite sides of the plunger, substantially straight roller supporting elements resiliently supported between said members across the top of the barrel of the syringe transversely of the plunger, and a roller journaled on each of said elements, said rollers engaging opposite sides of the plunger and being resiliently urged thereagainst to non-frictionally restrain movement of the plunger LOGAN EISELE. 

